Maximum availability and mineralogical control of …

Aging of AOD slag under the atmosphere can oxidize trivalent chromium to hexavalent chromium, which could be leached out by rainwater. According to the simulation, the chromium concentration in leachates was controlled by the freely soluble pseudo-binary phases in the pH = 7.0 leaching process and controlled by the Cr 2 O 3 phase in the pH = 4 ...

Transport and fate of hexavalent chromium in slag–soil ...

2019-3-28 · The transport and fate of hexavalent chromium Cr(VI) in slag–soil system, which remain poorly understood, are of great importance for environmental risk assessment and pollution control of Cr(VI) in soil and groundwater. Based on the migration behavior of Cr(VI) in the chromium-containing slag under the effects of rainfall, the transport and fate of Cr(VI) in soil …

Chromium(VI) Handbook | Request PDF

In the environment, chromium is present mainly in the oxidation states, in the trivalent [Cr(III)] and hexavalent [Cr(VI)] forms (Ghosh et al., 2003; Guertin et al., 2016). Cr (III) is essential ...

Sustainable solidification of ferrochrome slag through ...

2019-8-1 · Ferrochrome (FeCr) slag was used as a precursor for the synthesis of a geopolymer. The effect of KOH concentration, liquid solid ratio (L/S), content of potassium metalisicate (KS) or potassium aluminate (KA), curing time on the unconfined compressive strength (UCS) and metal leachability of the synthesised geopolymer was investigated. A 10 M KOH and an L/S of 0.26 …

In situ bioremediation of hexavalent chromium in presence o…

2005-11-11 · 1.. IntroductionFerrochromium is a master alloy of iron and chromium, containing 45–80% Cr and various amounts of Fe, C and other elements. Ferrochromium is produced pyrometallurgically by carbothermic reduction of chromite ore (FeO·Cr 2 O 3).The main slag additives used are quartzite and aluminium oxide containing materials to compensate for the …

ferro chrome slag crushed aggregates

2021-11-8 · Ferrochrome slag and fine aggregate by Stone Dust Ferrochrome slag is a waste material obtained from the production of Ferrochrome an essential component in stainless steel It has been observed that Ferrochrome slag waste is a suitable material for highway pavement work This research work was conducted to know the performance of Ferro . More Detail

Release behaviour of chromium from ferrochrome slag ...

Huge amount of ferrochrome slag, a solid waste is being generated from submerged electric arc furnace during manufacturing of ferrochrome alloy. The …

Toxicological Review of Trivalent Chromium (CAS No. …

2014-3-24 · Chromium (Cr) is a metallic element belonging to the first transitional series of the periodic table. Elemental chromium has a CAS Registry Number of 7440-47-3. The three most stable forms in which chromium occurs in the environment are the 0 (metal and alloys), +3 (trivalent chromium), and +6 (hexavelent chromium) valence states.

Aqueous chemistry of airborne hexavalent chromium …

2018-8-1 · Hexavalent chromium exists in solution as CrO 42−, HCrO 4−, and H 2 CrO 4 (Palmer and Puls 1994 ). At pH around 1, chromic acid (H 2 CrO 4) is the dominant form, whereas at pH values between 1 and 5, HCrO 4− is more favored. Dichromate (CrO 42−) becomes more dominant at pH values greater than 6 (Davis and Oslen 1995 ).

Original Research Homogeneous Photocatalytic Iron …

chromium compounds. Trivalent and hexavalent forms in aqueous systems cause diarrhea, and according to WHO (the World Health Organization), its permissible level in surface water bodies is 0.05 mg/L and its Pol. J. Environ. Stud. Vol. 28, No. 5 (2019), 3745-3752 Original Research Homogeneous Photocatalytic Iron Slag Reduction Cr6+ from Chromium ...

Hexavalent chromium removal by ferrochromium slag ...

2005-8-10 · The Cr(VI) concentrations of water contacted with ferrochromium slag (W/FS=10) in a closed cycle after 50 batches were found as 0.61 mg/l. Also, reduction of Cr(VI) to Cr(III) and a subsequent precipitation of Cr(III) by using ferrochrome slag (FS) in a …

Chromium in the environment of Finland

1998-6-11 · Large amounts of slag containing 3.7% chromium (as Cr 2 O 3), the by-products of ferrochrome and stainless steel production in Finland, are dumped into the basin dammed off from the sea . Chromium is also present in the slags of the non-ferrous metal industries, cement facilities, iron and steel industries and secondary metal industries.

Chromium | SpringerLink

Chromium for industrial use comes from chromite ore that contains chromium as an oxide, together with varying amounts of iron, aluminum, and manganese; ferrochrome is the primary refining product of chromite ore. Chromium is an important metal in several alloys, notably in stainless and acid-resistant steels.

Journal of Cleaner Production

2019-10-11 · 1.2. Relevance of hexavalent chromium Chromium can occur in several oxidation states, but only trivalent chromium, Cr(III), and hexavalent chromium, Cr(VI), are common in near surface environments, while metallic chromium, Cr(0), is mainly produced by human intervention (Motzer and Engineers, 2004; Bartlett, 1991).

Chromium adsorption and Cr(VI) reduction to trivalent ...

Chromium as Cr(VI) is a industrially produced pollutant. Hexavalent chromium can be reduced to the trivalent state using various reductive agents or it can be removed from solution by surface-active adsorbents. In this study, both of these methods were …

Genotoxicity of Tri

2014-8-11 · Introduction. Chromium (Cr) is a heavy metal and a well-known environmental contaminant mainly exists in hexavalent [Cr(VI)] and trivalent [Cr(III)] states .High levels of exposure to Cr(VI) occurs in chromate manufacturing, chrome plating, ferrochrome production and stainless steel welding.

Conditions for mutual conversion of Cr(Ⅲ) and Cr(Ⅵ) in ...

2019-6-5 · According to the above results, oxygen is a necessary condition for transforming trivalent chromium ions into hexavalent chromium ions in aluminum chromium slag. At 1500 °C, whether it is sintered in a reducing atmosphere or in an air atmosphere, the Al 2 O 3 -Cr 2 O 3 solid solution of the aluminum chromium slag reacts under the action of CaO ...

Chromium as an Environmental Pollutant: Insights on ...

Chromium exists in several oxidation states, but the most stable and common forms are Cr(0), the trivalent Cr(III), and the hexavalent Cr(VI) species. Cr(0) is the metallic form, produced in industry and is a solid with high fusion point usually used for the manufacturing of steel and other alloys.

Toxicity assessment and geochemical model of chromium ...

The Pourbaix diagram of the Cr-H2O system indicated that trivalent chromium, such as Cr(OH)4(-), is the major chromium species in the experimental Eh-pH region considered. However, toxic hexavalent chromium was released with maximum concentrations of 30 µg L(-1) and 18 µg L(-1) at L/S 10 and 100, respectively, during the earlier leaching stage.

Chromium Compounds

2021-6-25 · Chromium is a naturally occurring element in rocks, animals, plants, soil, and volcanic dust and gases. (1) Chromium occurs in the environment predominantly in one of two valence states: trivalent chromium (Cr III), which occurs naturally and is an essential nutrient, and hexavalent chromium (Cr VI), which, along with

Particle-Size Distribution of Chromium: Total and ...

2018-5-31 · chromium is converted to hexavalent forms in biological systems. Hexavalent chromium, however, readily crosses cell membranes and is reduced intracellularly to trivalent chromium (Goyer, 1986). The known harmful effects of chromium in humans have been attributed to the hex- avalent form. Hexavalent chromium is very

Chromium in Environment, Its Toxic Effect from Chromite ...

2018-7-6 · Chromium in the trivalent and hexavalent forms are important in the Eh–pH range of natural aquatic systems. Chromium in the hexavalent form is found to be toxic to plants and animals, and has been found to be a strong oxidizing agent, corrosive and a possible carcinogen (Richard and Bourg 1991 ; Fruchter 2002 ).

Valuable waste

2018-10-19 · toxic nature of trivalent and hexavalent chromium makes the flue dust from the ferrochrome industry hazardous. About 400-500 kg residue is generated per tonne of ferrochrome metal produced – this residue includes slag, flue dust and sludge [6]. Flue dust generation is increasing enormously as

In situ bioremediation of hexavalent chromium in presence ...

2019-5-15 · Stability of chromium in the ferrochrome slag dumps and leachate are affected by pH, redox potential and the presence of other metallic species in the slag. It is desirable to keep chromium in slag dumps in the trivalent [Cr(III)] state because trivalent chromium is 1000 times less toxic to living organisms than the hexavalent form [Cr(VI)].

Case Study: Chromite mining and processing

hexavalent chromium.8 Sources of chromium emissions to air include coal and oil combustion (primarily trivalent), chrome plating (hexavalent) and industrial cooling towers (hexavalent).8 Chromium is removed from the atmosphere by fallout and precipitation over about 10 days.8 Smoking can contribute to chromium levels in indoor air as tobacco

Recovery of Chromium from Ferrochrome Slag

2019-7-12 · of chromium and renders the slag harmless. In this paper industrial waste was collected from GTS industries and used in the subsequent experimentation. Ferrochrome slag is treated with lime to conduct slag-lime solid-solid reaction. Chromium present in the slag reacts with lime to form mixed chromates. The reaction is conducted at 973K, soluble

Environmental and technical assessment of ferrochrome …

Chromium Concrete Ferrochrome slag Leaching Immobilization abstract Ferrochrome slag is a major solid waste generated from submerged electric arc furnaces during manufac-turing of ferrochrome alloy. The waste slag has excellent mechanical and engineering properties for uti-lization as concrete aggregate material.

1988 OSHA PEL Project

The ACGIH has established an 8-hour TWA of 0.5 mg/m 3 for chromium, which is a steel-grey metal. In the final rule, OSHA is retaining the former 8-hour TWA PEL of 1 mg/m 3 for chromium metal. According to the ACGIH, a 0.5 mg/m 3 TLV-TWA for chromium "should be adequate to prevent pulmonary disease or other toxic effects" (ACGIH 1986/Ex. 1-3 ...

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Microbial Detoxification of Hexavalent Chromium from Chromium-Containing Slag (School of Metallurgical Science and Engineering,Central South University,Changsha 410083,China) Online: 2013-03-25 Published: 2013-04-23

Hexavalent chromium removal by ferrochromium slag.

2005-11-11 · Hexavalent chromium removal by ferrochromium slag. Erdem M(1), Altundoğan HS, Turan MD, Tümen F. Author information: (1)Department of Environmental Engineering, Firat University, 23279 Elaziğ, Turkey. The aim of this study is to demonstrate the potential of Cr(VI) generation during jigging operation applied for ferrochrome recovery from slag.

The Colorful Element Chromium | Periodic Table | ChemTalk

Trivalent chromium is a vital micronutrient and aids the efficiency of insulin in individuals who struggle with glucose intolerance. Hexavalent chromium or chromium is extremely toxic as it can cause cancer, destroy red blood cells, and give rise to …

Hexavalent chromium removal by ferrochromium slag

Journal of Hazardous Materials B126 (2005) 176–182 Hexavalent chromium removal by ferrochromium slag Mehmet Erdema, H. Soner Altundogan˘ b, M. Deniz Turanb, Fikret Tumen¨ b,∗ a Department of ...